Projector lamp



July 17, 1928.

I T. HALL PROJECTOR LAMB I5 Sheets-Sheet Filed lAug. 24, .1921

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July 17, 1928.

`T. HALL PROJECTOR LAMP 5 Sheets-Sheet Filed Aug, 24, 1921 IMIII llmlllv "IIC 1 1 :EE: 1F

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T. HALL PROJECTOR LAMP Filed Aug. 24, 1921` 3 Sheets-sheet 5 Mw i e Patented July 1'7, 928.

UNITED STAT-Es' PATENT.' omen.

-THEODORE HALL, OF BROOKLYN, NEW YORK, ASSIGNOB TO THE SPERBY GYROSCOPE COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OI' YORK.

rnomc'roa Lani'.

4 Application led August 24, 1821. Serial No. 494,818.

l vThis invention relates t arc lamps, especially to that type o f arc lamp known'as the high intensity flaming arc. One of the objects otI the invention is the provision of n an arc lamp which is especially adapted for l likely to be damaged by the heat of the arc if for any reason said main electrode burns back too far. To prevent such damage to the auxiliary electrode, I have provided means for indicating when the said electrode is iu danger of bein damaged. j

Another object o my invention is the provision of a novel and improved form of means for holding the negative lelectrode.

Still another object is to provide means for cooling themain and auxiliary electrodes which shall be an' improvement over the cooling means shown in my application No. 459.765, tiled April 8, 1921, for air-cooled projector lamp.

()ther objects and advantages will become apparent as the description of the invention is hereinafter developed.

Referring to the vdrawings wherein I have shown what I now consider to be thepreferred forms of my inventionr.

Fig. 1 is a side elevation of my improved arc light mechanism as applied to a motion picture projector lamp, part of the lamp housing being shown in section. Fig. 2 is a sectional view through a por-v tion of my arc light mechanism shown in connection with a spot-light.'

Fig.` 3 is'a detail plan view'of-the holder lfor the negative electrode.

Fig. 4 is a detail view showing means for maintaining the positive electrode in firm contact with a current conducting member.

Fig. 5 is an elevation'partly in section showingpart of the Ventilating and feeding means. l

v Fig. 6 is a vertical sectional view of part of themeans for rotating and .feeding the positive electrode.

Fig. 7 is a view in end elevation of the parts shown in Fig. 6.

Fig. 8 is anelevation, partly in section,

of other parts of the mechanism. V l y Fig. 9 is a View at right angles to Fig. 7. Fig. 10 isa wirin diagram. Fig. 11 is a view o a detail.

. Fig. 12 is a vertical sectional view showelectrode feeding ling the means for conducting air over the positive and auxiliary electrodes.

The reference numeral 1 designates the housmg of a motion picture projector having the usual vframe 2 which supports conventional projecting lenses (not shown). Within the housing 1 is a plate 3-whicl1 carries the electrodes and the operating mechanism therefor.

Plate 3 may be pivoted to standards 4- projecting upwardly from a second plate 5, the plateY 3 beingthus movable about a horizontal axis with respect to` plate 5. .The

' latter is shown pivoted at 6 to a base plate 7 for movement'about a vertical axis. Base vplate 7 is provided on opposite sides with lugs slidably engaging suitable guide rods supported on the floor of the lamp housing. 011e of said lugs is shown at 8 and the correplate 7 and hence the lamp mechanism, be shifted longitudinally in rhousing have shown part of rod 9 threaded and may 1, I passing through an internally threaded preise?,

tion 10 on base plate 7. Rod 9 is rotatably mounted in bearings 11 on the floor of the abling thev operator to conveniently adjust the lamp mechanism to the right on left, I

have shown .a rod 14, threaded through alug 15 carried vby base plate7, said rod 14 carrying at one end a grooved head 16. A projection 17 on one of standards 4 engages the groove in said head. A knob 18 is fixed on rod 14 outside thelamp housing. Another knob 19 is secured to a rod 20 which has a portion threaded throughaI projection spondingguide rod at 9. In order that base 21 on plate 5. `A downwardly extending liange on plate 3 abuts against the end of the threaded portion of rod 20. The plate V3 and lamp mechanism carried thereby may 5 thus be raised or lowered Within housing 1 by suitably turning knob 19. The rods 14 and 20 maybe made in Sections and suitable universal joints may be interposed between the sections of the respective rods. Such l universal joints may be of the form shown in Figure 11, wherein one section of rod 14 is shown pivotally connected to a sleeve 22, the other section of said rod being connected to said sleeve for movement about an axis at l right angles to the axis of the pivotal connection of the .first mentioned section. Rod 9 may be provided with' a collar 9 to limit endwise .movement thereof.

To the upper face of plate 3 is secured a metal-frame 23, insulating material 24 being said shelf being curved, as shown in Fig.

'4 to extend around a portion of the pe riphery of said electrode. Current may be led to said positive electrode through frame 23 and shelf 25 and for the purpose of main- 3) taining said electrode in firm contact withv i said shelf,"I have' shown a grooved block 26 fitting over electrode .13 above shelf 25, a tension spring 27'be'ing connected at one end to a bail 28 attached to said block. The

l5 other end ofspring 27 is connected to the .base of frame 23, so thatsaid spring thus lexerts a downward pressure upon electrode 13.- l

The positive electrode extends through 40 a sleeve 29 whichis rotatably mounted lin the upper portion of a carriage 30.. The latter is mounted for slidin movement,

upon a rod 31 which is rotata lymounte-d l at one `end in a plate 32 secured to4 frame 46 23 land at its other end in a lateral extension 33 of anl arm 34 attached to said plate 32. Carriage has attached thereto, and integral therewith an internally threaded sleeve 35 through which Apasses 'a threaded 50 rod 36, which rodis mounted for rotation in plate 32and 'extension 33 and is shown extendingparallel to rod 31. The sleeve 35l may be connected by a web ,37 withthe portion 38 of carriage 30 that surrounds rod 31. 55 Interposed between said portion 3,8, and an arm 39 extending'laterally from sleeve 35, is a gearwheel 40 having akey 41 .engaging in a keyway 42 provided in -rod 31. Due to this construction it lwill be seen that when- 00 Cever the carriage 30 moves along rod 31, gear 40 is moved with saidcarriage and that whenever rod 31 is turned, gear 40 will be turned also. Turning ofv rod 31 has, at the 'means to be described latex'.

ing rod 36 which may be accomplished by Gear 40 meshes with a gear 43 secured to sleeve 29, so that rotation of said gear 40 results in rotation of the positive electrode. l have provided means for constantly rotating rod ,31, and hence the positive electrode 13, during the operation of the lamp and for operating rod 36 to'maintain the crater of said electrode at a .given position. Such means is shown in Figs. 1, 5, 8 and 9 and may be constructed and arranged substantially as follows:

Supported outside the housing 1 and to the rear thereof is a motor 44. The shaft 45 of this motor-drives a fan 46 located within a housing 47,`\vhich fan serves to force air over the electrodes and their holders as will appear more fully hereinafter. Above vthe housing 4T is a casing 48, lwithin which is a worm shaft 49, the worm of which meshes with a worm whe-el 50. Shaft 49 is driven by shaft 45 through a spring 51 which connects said shafts. I iind the spring 51 desirable since it prevents any vibrations of fan 46 or shaft 45 from being transmitted to worm shaft 49 and also presses the motor shaft firmly in its bearings, thereby minimizing vibrations thereof. Worm wheel 5() is fixed on a shaft 52 which projects through the rear end Wall 48 of casing 48. 'lhe end of said shaft 52 which extends outside said casing carries a disk 53 which has an eccentric pin 54, which pin is positioned within the forked end 55 of an extension 56 of a rocking arm 57. The latter -is pivoted intern'iediate its ends at 58 to the outside of wall 48 of casing 48. It will be seen from the above description that as long as motor 44 is inl operation, arm 57 will be oscillated about its pivot 58.

Pivotally connected adjacent one end of arm 57 is a pawl 59Which cooperates with a ratchet wheel 60. A spring 61 serves to maintain said pawl in engagement with said ratchet. The latter is provided with a square opening which' itsover the squared portion of a rod 62. Said ratchet wheel 4is also provided with a Lhub 63V rotatably mounted in a 'bushing 64 carried by the rear end wall 48 of housing 48. `A ring 65 is 'fixed to hub 63 and is adapted to abut against the end of bushing 64. A. resilient washer 66 maybe interposed between said bushing and ring, if desired. By the above 'described' construction the rod 62 may be removed from ratchet without disturbing said ratchet. rod 31`tl1rough a suitable universal connection such as shown in Fig. 11.

It will be apparent that as long as motor 44 1s in operatioruth'e positive electrode 1.3

.will bev rotated through pawl 59, ratchet 60,

Rod 62 may be connected toI rods 62 and 31, and gear wheels 46 and 43.

feeding Yof the positive electrode, I have For rotating the threaded rod 36 to causeA lao shown -apawl 67 pivoted to arm 57 and adapted to engage a ratchet'wheel l68- on the be of the type previously ldewhich ma henever, durmgthe operation scribed.

.. `of motor 44, the pawl 67 engages ratchet 68,

rod`36 will lbe turned to feed electrode 13 forwardly. Anarm 73 is connected at one end to pawl- 67 -and passes through the forked end 74 of a .strip 75 connected to the armature 76 of an electro-magnet 77V I' within casing 48. Strip 75 yextends from the armature of magnet 77 thru an opening in wall 48 as shown. vAs long as said magnet is de-energized a spring 78 holds armature'v 76, strip 75 and arm 73 in such posit-ion 'that pawl 67 does not engage ratchet 68 during the oscillation of aim 57. 'Upon the energization of said magnet', armature 76 is raised'and thereby arm 73 is pushed upwardly by strip'75 to tilt Vpawl 67 into engagement with ratchet wheel 68.' As long as said magnet 77 remains energized, ratchet 68 is turned by arm 57 through pawl 67 and arm 36 is. thereby turned to feed carriage and electrode 13 forwardly. Upon the deenergizat'ion of magnet 77, armature 76 is moved by spring 78 to. pull arm 73 doWn- 36-wardly, whereupon pawl 67 is tilted so that `itrwill not engage ratchet 68'.

For controlling the 'energization of magnet 7 7 and hence the feeding of the positive electrode, I may utilize the third or auxiliary electrode system. This comprises an auxiliary electrode 79 which is shown carried by the end of a rod 80 and is positioned above the positive electrode `and adjacent the arc. The said auxiliary or third electrode is shown as a cylindrical mass ofdmetal, such gi cop er, provided with heat radiating fins Fig. lff'electrode 79' is connected electrimains. As the positive electrode burns away, the arc flame approaches the tip of nose 82. and current flows from 'the arc,

through electrode 79 and v'magnet 77, the;l

' wlll glow feebly, but if the are amount of current increasingI as the are flame approaches the third electrode. Magnet `77 may thus be energized to cause forward feeding of the positive electrode, the 'feed' ing ceasing when the positive crater is brought back to a predetermined position suchl that. insuicient current for attracting armature 76 Hows through magnet 77. The crater of the positive electrode is thus 'maintained at a 4given position, the burning away of said positive electrode resultingjn with a downwardly inclined, forwardly projecting nose 82. `As shown in` attraction of armature 76 and consequent feeding of said electrode back to its predetermined position. Since the gas surrounding the arc flame is conducting, it is not essentialthat said flame actually touch the third electrode in order for feedlng to occur. The third elrctrode 1feeding system disclosed is especially applicable in connection with flaming arcs of the high-intensity type, since such an arc has Aa'wellfdefined tail flame; and it is this type of arc that I prefer uti lizing in connection Vwith'the lamp mechanism herein described. f

The rod 8() which carries the third elec trode 79 may be vthreaded through a bracketA 84 secured to and insulatedfrom plate 32. Said rod extends outside the housing and is there provided with a handle 85. The latter is so positionedJ withrespect to nose 82 that when said handle is pointed downwardly,

as shown in Fig. 1, said nose is in its lowermost position adjacent the arc. By turning handle 85, the third electrode may be adjusted toward or away from the are. In

order that nose 82 may be in its lowermost position adjacent thel arc, handle 85 should .not be turned through a fraction of a revolution during adjustment of the third electrode,.but should be rotated through one or Vmore complete revolutions, so that at the end of the adjustment said handle is again pointing downwardly. Rod 80 is shown'in sections, between which areV interposed a' block 86 of insulating material and also uni- Versal joint 87, such as previously described. It will be seen that if for any reason the positive-electrode should burn back too far,

as because of disarrangement of the feeding' mechanism, or because carria e130 has been fed to its eXtreme forward limit, the third electrode may become immersed in the intensely hot are flame and may thereby vbe seriously damaged. In'order .to prevent such damage, I have provided means for' .apprising the operator of the proximity ofl ,the arc with respect`to the third electrode.`

I have shown such means as comprising an incandescent lamp 8,8 in circuit with the third electrode.- As shown in Fig. 1, said lamp 88 may be positioned on top of casing .48 where it can readily be seen by the oper? ator. Said lamp 88 may be so designed that when suiiicientjycurrent' flows through the third electrodei'to' cause'- feeding, the lamp ame should approachv closer to the third electrode, the

increased current will cause the'lamp 88 to glow morebrightly, the .brilliancy of thel glow increasing toa maximum when the third electrode is immersed in the arc Haine. Thus, by observing lamp 88, the operator will-be kept informed of t-he proximity of the are tothe third electrode and can. break the circuit through the arc when said third electrode is in danger of being damaged.

The negative electrode 89 is supported by a hollow bracket 90 which is secured to and insulated from frame 23. Adjacent its arcing end, said negative electrode rests in a seat 91 in the upper portion of 'bracket 90.

Adjacent its other end said electrode is clamped in and passes through the upper portion of an arm 92 which forms part of a carriage 93. Said arm 92 is-pivoted between standards 94 for movement about a horizontal axis, said standards being carried by the base portion 95 of carriage 93. Said carriage is provided with a tubular bearing member 96 and a forked member 97 through which pass guide rods 98 extending fiom bracket'90, said carriage being thus supported by said guide rods for sliding movement thereon. Current may be led to the negative electrode through-A bracket 90,A a socket 99 for receiving the tip of a conductor being shown connected to said b-racket. The said negative-electrode is shown positione`d at an angle to the positive electrode, as is common in high intensity fla-ming arc lamps. For maintaining the electrode '89 firmly engaged with seat 91, thereby insuring good electrical contact, aspring 101 may' be provided. Said spring is fastened at one end to the Hoor 95 of carriage 93 and at its other end to a downwardly projecting extension 102 from arm 92. It will thus be seen that spring 101 forces arm 92 downwardly and thus holds the negative electrode in firm contact with seat 91. Current may also be led to the elect-rode 89 through arm 92, a flexible metallic strip 103 being shownconnecting bracket 90 with eXtension 102 for this purpose. y

For feeding the negative electrode to maintain constant the length of theA arc, the following mechanism may be provided. A link 104 is pivotally connected at one end to carriage 93, said link being shown fitted into a socket 105 which is pivoted to said carriage, while at its other end, said link is pivoted in any suitable manner to a traveling nut 106. A threaded rod 107 passes through said nut, said ro'd being rotatably supported by brackets 108 depending from arm 34. Nut 106 is provided with an extension 109 which is slidably mounted on a rod 110 carried by said brackets 108. Connected to rod 107 by a universal connection 111, which may be similar to universal connection 22 previously described, is a rod 112 which eX- tends throughv casing 48. On the outside of the rear wall 48 of said casing is a. ratchet wheel 113 fitted over a squared portion of rod 112. Ratchet wheel 113, may have a hub 114-and, ring 115 which perform the same functions as the corresponding parts, previously described, of ratchet wheels 60 and 68. A pawl 116 is pivoted to the end of arm 57 opposite from pawls 59 and 67 and is adapted to cooperate with ratchet 113. Connected to an extension 1.17 of pawl 116 is a-v tension spring 123 is connected at one end to rod 118 and at its other to a suitable adjust- `ing member 124 and ,tends to pull said ro'd to the right in' Fig. 5 and thereby lto move strip 120 laterallyto raise armature 122.

Magnet 121'is connected across the arc and Y is thus responsive to the voltage across the are, which in turn depends upon the are length. Spring 123 is so adjustedthat as long as the currenttlirough magnet 121 docs not exceed aYpredetermined'amount corresponding to the desired arc length, rod 118 is pulled to the right (Fig. 5) and armature 122. is thereby held in raised position and pawl 116 tilted so as not to engage ratchet 113. When" the arc length increases beyond the 'desired amount, however, the current through-magnet 121 becomes sufficient to at-l tract armature 122. Strip 120 is thus moved to the right in Fig. 8, against the action of spring 123, which resultsin movement of rod 118 to the left in Fig. 5, (Figs, 5 and 8 bein-g views on opposite sides of wall 48'), so that pawl 116 is tilted into position for engaging ratchet 113 as arm 57 oscillat'cs. Ro-

tation pf said ratchet 113 results in feeding. of the negative electrode toward the positive electrode and this feeding continues until the proper arc` length has been restored, whereupon spring 123 again raises armature 122 and tilts pawl 116 to its inoperative po sition. y

It will thus be' seen that means are providedl for automatically rotating the positive electrode, feeding said electrode to maintain the crater thereof at a. given point and feeding the negative electrode to maintain constant the length of the arc. For enabling the operator to perform said functions` or modify the action of said mechanism manually whenever desired, rods 62, 69 and. 112 may be provided with knobs 125, 126 and 127 respectively. Suitable blocks of insulation.

(not shown) are preferably interposed between sections of rods 31, 36 and 107 as shown in connection with y'rod 80.- For accurately maintaining thepawls 59, 67, and 116 in the plane of their respective ratchet wheels, a guide rod 142 maybe mounted behind said pawls, as shown. y

Whenever for any reason the current in mains 83 increases beyond its normal value, trouble may result, since the current through magnet 121 is thus increased and feeding of the negative electrode toward the positive is Leva-591 y 5 caused, even Athough the roper arc length has been attained. If suc increase incurrent persists sufficiently, the negative elec-A tro'de may actually be fed into' contact withl the positive. To avoid the actuation of the negative feeding mechanism by such current mcreases, I have provided a compensating winding 140 or magnet 121, suchl winding', being wound oppositely to the magnet windriage reaches-its extreme forward position, it is designed to run not quite off the threaded portion of the rod. Thereupon fur.

ther rotation of the rod will'cause said rod to move backwardly against the action ofV a spring 128 which teiids to hold saidrod thrust forwardly. The threaded part of rod '3 6 will thus be disengaged from'sle'eve 35 ofv carriage 30, so that said rod may thereafter rotate freely without affecting-the position of the carriage. B backward. rotation of rod69, the threaded7 portion of rod 36 will again engage the carriage and move it to its rearward position.

To strike the arc, knob 127 ma be pulled back, thereby sliding rod 107 ackwardly in its bearings 108 against the action of a spring 129 and. ythusv moving electrode 89l into engagement with electrode 13. 'When Vknob 127 -is released, saidspring 129 will restore electrode 89 to its normal position, -thus drawing the arc.

It will be noted that by the above def scribed, construction of the holder for the negative electrode, I avoid the objections present in prior structures wherein part of Y the holdingl means extends over the upper above seat 9 1.

surface of the negative electrode adjacent its arcing end and is thus exposed to theintense heat of the arc. In Vthe -holding means which I have provided for the nega.-

-. tive electrode, theonly part that extends over said velectrode is a portion of thje arm 92, which is positioned at the end ofsaid electrode remotel from the arc and is 'hence not exposed to. the heat thereof tothe extent that it would be if it were positioned The latter, as is shown in Fig. 3, may be formed with inclined sides and serves .to hold the negative electrode in correct alignment with the positive. At vthe same time said seat serves to conduct heat from said electrode 89 and to prevent 'spindling of said electrode beyond the end of saidseat nearest the arc. A pin 100 is shown mounted in arm 92 for engaging the end of 'electrode V`89 to -the movement Y thereof when said electrode is being inserted in said arm. 'Arm 92 is shown .provided with a movable clamping section, 92', which is secured 'to saidarm by a screw 9 so 70 that the electrode 89'may beV firmly clamped tosaidarm. Y v The housing 47 has an opening 47" in the bottom thereof through' which aiigmay be drawn byfan 46 and forced out through 75 av conduit f130,.whereby strong currents of air are produced which are directed'to vcool the arcing electrodes and' their holders as well as the 'auxiliary or third electrode.

As has" been previously pointedout, the so frame 23 and standard 90 are hollow. The

.air conduit 1'30 which. communicates with housing 47 extends forwardly, as shown', for. directingair toward theframe 23.`` I have@ found that it is not necessary to extendl conduit 130 the full distance to -frame 23, and

- thus avoid the necessity of: providing joints inthe conduit to allow for-the adjustments of the lamp mechanism in the 'housing 1 and also avoid insulating said conduit. In order 90 that* the stream of air may be accurately Adirected into the opening 131 in frame 23 without escaping upwardly before it reaches said frame, the walls of said conduit may be inclined to provide a Asomewhat restricted opening Afor the escape of the air, or as is shown, an overhanging lip .132 may be provided. The air, upon leaving conduit 130, rushes Vinto opening 131 in frame 23, whence -part of the air passes upwardly in said frame, around shelf25 and block. 26 and' lthence around the third electrode 79 and cooling fins 81. As is shown clearly in Fig. 12, the sides of frame 23 are curved around shelf 25 and spacedtherefrom to provide 105 l air passages therearound, land said' sides are also curved inwardly toward the third electrode 79 to direct air on opposite sides thereof. -Part of the air that enters open- `1 ing 131 continues out through the hollow. 11o

bracket90 cooling said bracket and seat 91 and thence out into contact with the negative electrode 89 and carriage 93. Simple and effective'means for extractingheat from the arcing electrodes and their holders and from the third electrode is thus provided. v

The rush of air through frame 23 and bracket 90 also serves to ventilate the lamp housing 1.- Air outlet openings 132 are shown in the upper portion of said housing and a chimney 133 may also be provided for the escape of. air.; Suitable openings (not shown) may be provided adjacent the bottom of said housing or in the floor thereof, for admitting air -tothe interior of the housing to aid in theventilation thereof,

as will be readily understood.

The lamp mechanism of Fig. 1 may obv viously .be employed for a variety of uses.

In Fig. 2, for example, such mechanism is 'sae shown within the casingll o f a spot-light housing havin a condensing lens 135. In this case the rame 23 is shown su ported on and insulated from a base mem er 136 therewithin.

In accordance with the provisions Aof the I patent statues, I have herein described the principle of operation of my invention, together with the ap aratus, which I now consider to represent t e best embodiment thereof, but I desire to have it understood that the apparatus shownis only illustrative and fin firm cont-act with said seat, means that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others' omitted without interfering with the cmore general results outlined, andthe invention extends to such use.

Having described my invention what I claim and desire to secure by yLetters, Patent is: i

i 1. In an arc lamp, a metallic member having a seat for receiving a portlon of anelectrode adjacent thearcing end thereof, an arm for supporting the opposite end portion of said electrode, a support to which said armh .A is pivot-ally connected, a spring-cooperating i with said arm to malntain said elect-rode 1n 35 firm contact with said seat, means for lead-l ing electric current to said seat and means for circulating a current of`air under said seat to cool the same.

2. In an arc lamp, a positivel electrode holder and a negative electrode holder the' latter comprising a member having a seat for partial y surrounding an electrode adjacent the arcing end thereof, means for receiving the opposite end portion of said electrode, a carriage to which said means is a shelf for receiving an electrode, said shelf ivoted, spring means cooperating with said rst named means to tilt the electrode into rm engagement with said seat, means for slidably supporting said carriage and feed- "ing means for both electrodes on said positive electrode holder and means connecting said carriage with said feeding means for feeding the negative electrode.

3. In an arc lamp, an electric conducting 'member having a seat for partially surrounding an electrode adjacent the arcing end thereof, a carriage for receiving another portion-of said electrode, means acting on said carriage for maintaining said electrcde or 'leading .current to 'said electrode through said carriage, and means for causing a cool- .ing fluid to pass adjacent said seat for ex- `tracting heat thereform. 4. In an arc lamp, a housing, a feed conrovidedo with opentrolling electrode positioned within said housing adjacent the arc, said electrode Ahaving a nose portioninclined downwardly toward the arc, arotatable rod connected to *said electrode', a relatively stationary member through which said rod is threaded, said rod extending to the outside of said housing, and a handle connected to said rod outside said housing, said handle being connected with said rod in a given relation to said nose to indicate-when the latter is .in its correct position.

5. In an arc'lamp, a housing, a feed controlling electrode positioned within said( housing, said electrode having a nose portion vextending toward the arc, means comprising a member extending to theV outside of said housing for adjusting vsaid electrode with respect to the arc and means for indicating when said nose portion is in its correct positlon.-

l In anarc lamp, a housing, a feed controlling electrode positioned within ysaid housing, said electrode having a nose portion inclined toward the arc, means com'- 'prising a rotatable rod extending to the outside of vsaid housingrfor adjusting said electrode toward or away from the arc and means carried by said rod for indicating when said nose is in its correct position.

7. In an arc lamp, an electrode holder hav-- ing a passage therethrough, a separate means for producing a current of air, and a conduit for directing air from, said means to said passage, said conduit terminating short of said passage and having no physical connection therewith.

, 8. In an arc lamp, an electrode holder having a passage therethrough, a housing withinv which said holder is mounted, separate means outside said housing for producing a current of air, and means terminating short of said passage for directing air thereinto being positioned within the hollow of said frame,- a block 'above said shelf for fitting over said electrode, resilient means within said frame for pressing said block toward said shelf and means for passing air through said hollow frame.

10. In an arc lamp, a hollow frame having an interior shelf for receiving an electrode, the side walls of said frame being spaced from said vshelf to provide 'air passages therearound, an auxiliary electrode positioned above said frame, said side walls being directed inwardly`7 toward said auxiliary electrode for directing vair thereagainst.

11. In an arc lamp, a member pivoted intermediate its ends, a pair of pawls pivoted adjacent one end of said4 member, ratchet wheels adjacent said pawls, means for oscillating said member, means for maintaining one'of said pawls in enga ement With its corresponding ratchet whee means responsive to the position of the positive crater for causing. engagement of the other pawl, with its corresponding ratchet wheel, electrode rotating means controlled b the first men# tioned ratchet wheel, e ectrode feeding means controlled by the A second ratchet Wheel, a third pawl pivoted adj acent the opposite end of said member, a ratchet Wheel engageable by saidthird pawl, electrode feeding means controlled by last mentioned ratchet Wheel and means responsive to the length of the are for causing said third paWl to engage said last mentioned ratchet wheel.

l2. In an arc lamp, an oscillatable member, means for continuously oscillating said member, electrode feeding means for each electrode, and means for causing said mem'- ber to operate both of said feeding means.

13. In an arc lamp, an oscillatory mem ber, a motor for continuously oscillating said member, independent feeding means for both electrodes, and 'separately operable means for causing said member to operate eitheror both of said feeding means.

14. In an arc lamp, the combination with a pair of electrodes and separate feed control means for each electrode, of a motive means, a member continuously oscillated thereby, a plurality of pawls moved by said member, the positlon of one of said pawls -being controlledbythe feed control means of one electrode, and the position of the other of said pawls being controlled by the control means of the other of said electrodes, anda ratchet mechanism operated by each pawl for feeding the respective electrode.

` 15. In an-arc lamp, the combination with a pair of electrodes and separate feed control means for each electrode, of a motive means, a member continuously oscllated thereby, a pair of pawls moved by said member, the position of bne of said pawls being controlled by the feed control means of one electrode, and the position of the other of signature. v

THEODORE HALL. 

